I am totally confused as to what's causing this. I lost three of my Cichlids in a week. I checked the water parameters and they are all fine. Nitride, Nitrate and Ammonia all show zero using the liquid test kit. I see no signs of disease such as ich, fin rot, cloudy eyes. There isn't much aggression except once in a while when they chase each other. I do water change every week. Water temperature is at 80 and ph is at 8.0 I have had them since they were juviniles and now they were about 3 inches. I feed them twice a day only for couple of minutes, none of the food makes it to the gravel. I am feeding them NLS sinking pellets and Hikari veggie pellets. The only thing that I changed a month ago is increase the amount of water being changed from 25% to 50%. The fish that died seem to have no energy to swim. If anyone has any idea as to what might be happening or what I should look for I would really appreciate it. Thanks!